Insulated wall or roof constructions of the type in which compressible insulation boards, particularly formed plastic material, are positioned over a wall surface of a substrate, such as an outside or inside wall surface of a masonry, metal, or wooden stud wall, have suffered from problems with respect to suitable mechanical fasteners for securing the insulation board to the substrate.
Conventional mechanical fasteners utilized in such wall constructions have primarily consisted of nail or screw-type fasteners which are simply driven through the insulation boards and into the substrate for securing the insulation boards to the substrate. These types of fasteners present problems when securing compressible insulation boards to substrates inasmuch as the usual head on these types of screw or nail fasteners presents a very minimum bearing surface in contact with the insulation boards. As a result, the fasteners are often driven too far into the insulation boards or the insulation board later buckles from environmental conditions, both resulting in undesired compression, deformation or stress of the insulation boards causing a weakness in the securement of the insulation boards to the substrate.
Although washers or clips have been heretofore proposed for use with fasteners, particularly in roofing construction and the like, such clips or washers are usually specifically designed for the particular use and are not readily adaptable for use in securing compressible insulation boards to a substrate wall.
The above problems become more acute when, as is the usual case, a plurality of insulation boards are to be secured to a substrate wall at areas of butted edges of the insulation boards, which are often placed over a stud in the substrate wall. In these situations, a fastener has to be used for each insulation board and must be placed at a certain required distance from the edge of the insulation boards, which results in weakness in the securement of the insulation boards to the substrate since the fasteners may be too close to the edges of the stud.